Md. Farid Hossain
School of Agriculture and Rural Development, Bangladesh Open University, Gazipur, Bangladesh
Md. Anwarul Islam
School of Education, Bangladesh Open University, Gazipur, Bangladesh
Nipa Palm, Production, Uses, Importance, Mangrove Forest, Bangladesh
Sundarbans mangrove forest of Bangladesh
Conservation and Biodiversity
It was postulated that this species had an original distribution from Asia extending to Europe, Africa, and America. Its current range is now confined within the tropical Indo-West Pacific region, from Sri Lanka through Asia to Northern Australia and the Western Pacific islands, suggesting changing climatic conditions and/or the loss of versatile genotypes that can tolerate wider environmental conditions. ‘Mangroves’ is an ecological term referring to a taxonomically diverse assemblage of trees and shrubs that form the dominant plant communities in tidal and saline wetlands along sheltered tropical and subtropical coasts. Economically, mangroves are a great source of timber, poles, thatch and fuel and the bark is used for tanning materials; some species have food or medicinal value. Nypa fruticans is a species best adapted to grow in mangrove coastal areas with moderate only salt load, and circumscribing quite well the actual areas of occurrence of this palm in the gradient from seawater habitats to inland sites. The coastal zone covers 19 out of 64 districts/zilas facing or in proximity to the Bay of Bengal, encompassing 153 Upazilas. The zone constitutes 32 percent of the area and 28 percent of the population of Bangladesh. In 12 of these districts, 51 Upazilas face a combination of cyclone risk, salinity and tidal water movement above critical levels and are designated as “exposed coast” (Figure 1, green areas). The coastal zone covers an area from the shore of 37 to 195 kilometers, whereas the exposed coast is limited to a distance of 37 to 57 kilometers. Nipa is a monoecious and pleonanthic palm; it also exhibits viviparous germination as in many other mangrove species. The leaves of nipa palm can grow up to 10 m, and arise from a dichotomously branched underground rhizome that grows to about 50 cm in length [1, 22]. The species lacks a visible upright trunk, and the leaves appear from the ground. The younger leaves appear from the middle of the crown and push the older leaves aside before they dry and fade away, leaving bulbous leaf bases or scars behind. The diameter of the cluster could be up to 75 cm and a single leaf may attain a height of 8 m. The mature crown may contain 6 to 8 living leaves and 12 to 15 bulbous leaf bases at a time. The collection of leaves normally started from the 6-7-year-old plants within the plantation. A slanting cut, maintaining a 45º angle is used. The cutting height above the ground depends on the planting density. If the density is high, cutting is undertaken at 7 or 8 cm above the ground and in case of low density, at 5 or 6 cm. The season of harvesting was January to February as new shoot development begins in March. Nipa palm is utilized by humans for several purposes, such as roof thatching, wall partitioning, making of sun hats and mats, foods like edible young seed, aromatic tea from leaf blade, sugar from xylem sap, medicinal purposes, bio-ethanol production, and remediation of heavy metal from polluted sites [24-26]. Newly developed shoots are to be used as a vermicide. Ash from Nipa palm is used as an analgesic against tooth pain and headache. Dry leaves, petiole, stem wood, fruit residues etc. are used as fuel. In fishing rhizomes of Nipa palm are extensively used, facilitating the fishing net to float over the water surface. Farmers also report that Nipa palm in the river or sea attracts deep-water fish. Sap is a product of photosynthesis; frond (leaf) biomass is likely related to sap production. Nypa fruticans frond biomass is the crucial factor for sap/sugar production. Nipa palm is a tropical plant. The average minimum temperature in its growing areas is 20°C and the maximum 32-35°C. Its optimum climate is sub-humid to humid with more than 100 mm rainfall per month throughout the year. Nipa palm thrives only in a brackish water environment. It is rarely seen directly on the seashore. Optimum conditions are when the base and the rhizome of the palm are regularly inundated by brackish water. For this reason, nipa palm occupies estuarine tidal floodplains of rivers. The optimum salt concentration is 1-9 per mil. Nipa palm swamp soils are muddy and rich in alluvial silt, clay and humus; they have a high content of various inorganic salts, calcium, and sulphides of iron and manganese, contributing to the typical odour and dark color. The pH is around 5; oxygen content is low with the exception of the topmost layers. Typically, nipa palm forms pure stands, but in some areas it grows mixed with other mangrove trees.
American Journal of Agriculture and Forestry, 2015; 3(4): 156-160, Published online July 16, 2015; ISSN: 2330-8583 (Print); ISSN: 2330-8591 (Online)
Journal